Device for measuring repetitive identical time intervals

ABSTRACT

A shaft is journalled in a housing for turning movement about an axis; the shaft has a first portion and a second portion. A pendulum is fast with the first portion elongated radially of the axis for swinging movement about the same and a pair of anchor plates are mounted on the second portion axially spaced in parallel planes. The blades each have a first surface both of which face in one axial direction and a second surface which both face in the opposite axial direction. Each of the first surfaces is inclined to and has an edge portion which extends at least substantially radially of the axis and is convexly curved on a small radius in direction axially of the shaft towards the respectively associated second surface. A circumferentially toothed wheel is mounted and biased for rotation in a plane at least substantially normal to the planes of the anchor plates and parallels the axis so that consecutive teeth of the wheel engage first one of the first surfaces to slide along the same to and over the edge portion past the associated second surface while concomitantly imparting to the plates and thereby to the pendulum a swinging pulse and to subsequently abut against the other of the first surfaces where it again slides past the edge portion and second surface while the next-following tooth engages the first-mentioned first surface.

United States Patent Wittner 51 May 16, 1972 [54] DEVICE FOR MEASURINGREPETITIVE IDENTICAL TIME INTERVALS Rudolf Wittner, Johnstrasse 6, lsny,Allgau, Germany 221 Filed: Feb. 17, 1971 211 Appl.No.: 115,988

[72] Inventor:

Primary Examiner Richard B. Wilkinson Assistant ExaminerStanley A. WalAttorney-Michael S. Striker [57] ABSTRACT A shaft is joumalled in ahousing for turning movement about an axis; the shaft has a firstportion and a second portion. A pendulum is fast with the first portionelongated radially of the axis for swinging movement about the same anda pair of anchor plates are mounted on the second portion axially spacedin parallel planes. The blades each have a first surface both of whichface in one axial direction and a second surface which both face in theopposite axial direction. Each of the first surfaces is inclined to andhas an edge portion which extends at least substantially radially of theaxis and is convexly curved on a small radius in direction axially ofthe shaft towards the respectively associated second surface. Acircumferentially toothed wheel is mounted and biased for rotation in aplane at least substantially nonnal to the planes of the anchor platesand parallels the axis so that consecutive teeth of the wheel engagefirst one of the first surfaces to slide along the same to and over theedge portion past the associated second surface while concomitantlyimparting to the plates and thereby to the pendulum a swinging pulse andto subsequently abut against the other of the first surfaces where itagain slides past the edge portion and second surface while thenext-following tooth engages the first-mentioned first surface.

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DEVICE FOR MEASURING REPETITIVE IDENTICAL TIME INTERVALS BACKGROUND OFTHE INVENTION The present invention relates generally to a device formeasuring repetitive identical time intervals, and particularly to sucha device which is usable with great advantage but not exclusivelyformeasuring time intervals in musical and medical use.

Devices of the general type in question are already well known and areused primarily in musical applications where they are known asmetronomes. inasmuch as the use of the term metronome is thought tofacilitate discussion and explanation of the present invention, thisterm will be employed hereafter to designate the device according to thepresent invention. I wish it to be expressly understood, however, thatthe use of this terminology is not intended nor to be construed aslimiting the scope of the present invention to a device for musicalpurposes. Instead, the use of this term is for purposes of convenienceonly so as to facilitate explanation of the invention.

The known metronomes are, generally speaking, satisfactory in theiroperation. In other words, they fulfill their intended purpose. However,they suffer from the drawback that they are of comparatively largedimensions and thus are not readily transportable in the sense which isdesired. This does not mean that known metronomes are large in anabsolute sense; however, they are too large to be for instance readilyaccommodated in an instrument case or in the pocket of a garment, forinstance a lab coat or a doctor's white gown or the like. Of course,attempts have already been made to overcome this problem. There is, forinstance, the so-called thread pendulum which has not been foundsatisfactory because it does not contain a clockwork mechanism and thusdoes not provide audible signals which in many instances are desired, ifthey are not outright necessary. Other attempts have involved the comstruction of metronomes of requisitely small size, using semiconductorcircuits. This, however, has not been satisfactory becausesemi-conductor elements are highly susceptible to temperaturefluctuations and because the number of such elements used in anyparticular unit must be held relatively small to avoid making the unitvery expensive.

These above-mentioned approaches were used because there was generalagreement that in the art that regular priorart metronomes could not bemade small enough, that is that the pendulum could not be made smallenough and still be able to set a tempo of between 40 and 208 impulsesper minute because in small pendulums, wherein essentially the samefrictional forces would have to be overcome as in large pendulums, nosufficiently free and therefore accurate swinging movement was capableof being achieved.

SUMMARY OF THE INVENTION It is, accordingly, an object of the presentinvention to provide an improved device of the type under discussionwhich is not possessed of the disadvantages of the prior art.

More particularly it is an object of the present invention to providesuch a device which operates with great precision and uses ashort-length pendulum, and wherein the short length of the pendulum doesnot disadvantageously afiect the precision of operation of the device.

Still another object of the invention is to provide such a device whichhas the advantages of the previously known large-size metronomes,including also the audibility of its acoustic signals, and which on theother hand is substantially smaller than the prior-art metronomes andfulfills the requirements according to the present invention.

In pursuance of the above objects, and others which will become apparenthereafter, one feature of the invention resides in a device formeasuring repetitive identical time intervals, particularly for musicaland medical use, comprising a housing and a shaft journalled in thehousing for turning movement about an axis. The shaft has a firstportion and a second portion with a pendulum being fast with the firstportion and elongated radially of the axis for swinging movement aboutthe same. A pair of anchor plates is mounted on the second portion inaxially spaced parallel planes for movement therewith. These plates eachhave a first surface both of which face in one axial direction and asecond surface which both also face in the opposite axial direction.Each of the first surfaces is inclined to an edge portion which extendsat least substantially radially of the axis and which is convexly curvedon a small radius in direction axially of the shaft towards therespectively associated second surface. A toothed wheel, that is acircumferentially toothed wheel, is mounted and biased for rotation in aplane which is at least substantially normal to the aforementionedparallel planes and which parallels the axis. Consecutive teeth of thewheel engage first one of the first surfaces so as to slide along thesame to the edge portion thereof and to slide on the edge portion pastthe associated second surface while concomitantly imparting to theplates and thereby to the pendulum a turning impulse with successiveaudible abutment on the other of the first surfaces, and for thereuponsliding along the other of the first surfaces and the associated edgeportion beyond the associated second surface while simultaneously aconsecutive tooth abuts the first one of the first surfaces with anaudible signal.

The pendulum of course receives a small turning impulse from each toothof the toothed wheel, so that the loss of energy due to friction in thependulum mount is compensated-for during each swinging movement of thependulum so that the latter continues to swing with unchanged amplitude.Of course, in order to assure that the impulses imparted by the teeth ofthe toothed wheel do not influence the swinging amplitude of thependulum, they must occur precisely at the moment in which the pendulumpasses through its rest position. The teeth of the toothed wheel impartthis impulse by contacting the so-called anchor plates which are mountedon the shaft on which the pendulum is also mounted. Heretofore theconstruction of such anchor plates received little attention because thetime and the distribution of the impulses was of little consequencerelatively speakingbecause the energy supplied to the pendulum duringeach such impulse was relatively small with respect to the energy of theswinging mass. However, when the mass of the swinging pendulum issmaller and the lever arms involved are shorter, as in the constructionaccording to the present invention, the above features gain considerableimportance. By constructing the anchor plates in the manner alreadybriefly outlined above, I assure that the impulse is delivered preciselyor almost precisely at the time the pendulum passes through its restposition and that each impulse acts upon the pendulum for only a verybrief moment due to the selected inclination of the respective firstsurfaces and edge portionsand thereby assures that the frequency of freeswinging movement of the pendulum is not disturbed.

in order to further reduce to a minimum the friction between the platesand the teeth of the toothed wheel at the moment at which the respectiveteeth slide over the curved edge portions from the respective firstsurface to the respective second surface, the edge portions are curvedin the abovedescribed convex manner rather than terminating abuptly witha sharp edge as was customary heretofore. l have found it to beparticularly advantageous if the curvature resembles the surfaceconfiguration of an axially halved circular cylinder whose diametercorresponds to the distance between the first surface and second surfaceof the respective anchor plate, that is to the thickness of the anchorplate.

I have also found it to be advantageous if the material of the anchorplates and of the toothed wheel, or at least of the teeth thereof, is socoordinated that the least possible friction will arise from contactbetween them. An advantageous combination of materials is for instanceobtained if the toothed wheel, or at least the teeth thereof, iscomposed of a acetal resin and if the anchor plates are composed ofsteel. This also assures that the teeth of the toothed wheel, as long asthey slide on the non-inclined portion of the respective first surface,exert only a very small braking action upon the pendulum so that theideal circumstance of a freely swinging pendulum is furtherapproximated.

A further advantageous embodiment provides also for at least one endportion of the shaft carrying the pendulum, to be adjustably joumalled.This makes it possible for adjusting the anchor plates exactlysymmetrically with reference to the longitudinal axis of the pendulum,and also to obtain the proper distance to the center of the toothedwheel, circumstances which are of particular importance when the lengthof the pendulum is small. In this manner I achieve that the audiblesignals will take place at precisely equidistant time intervals if thependulum is properly adjusted also.

The novel features which are considered as characteristic for theinvention are set forth in particular in the appended claims. Theinvention itself, however, both as to its construction and its method ofoperation, together with additional objects and advantages thereof, willbe best understood from the following description of specificembodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a side view in a sectionedelevation and fragmentary illustration, of an embodiment of theinvention with non-essential components having been omitted for clarify;

FIG. 2a is a top-plan view of a detail of FIG. 1;

FIG. 2b is an end view, as seen in the direction of the line 2b ofFlG.l, ofa detail of FIG. 1;

FIG. 2c is a fragmentary detail view on an enlarged scale, of the samedetail shown in FIGS. 20 and 2b,-

FIG. 3 is a view somewhat similar to FIG. I but illustrating a detail ofan embodiment for journalling the shaft;

FIG. 4 is a cross-section illustrating a journalling screw for theshaft;

FIG. 5 is a front view of an embodiment of the invention;

FIG. 6 is a top-plan view of an embodiment of the invention;

FIG. 7 is a bottom-plan view of an embodiment of the invention;

FIG. 8 is a vertical section, and side elevation, of an adjustingarrangement according to an embodiment of the invention;

FIG. 9 is a perspective view illustrating a preferred embodiment of thehousing;

FIG. 10 is a fragmentary elevational view, on an enlarged scale, showingan embodiment of a pendulum;

FIG. 11 is a fragmentary sectioned detail view, on an enlarged scale, ofa further embodiment;

FIG. 12 is a fragmentary elevational view illustrating anotherembodiment of the invention concerned with an arresting device for thependulum;

FIG. 13 is a section taken on line 13-43 of FIG. 12; and

FIG. 14 is a top-plan view of FIG. 13.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Discussing now the drawing indetail it will be seen that in FIG. 1 I have illustrated an embodimentof the invention in which reference numeral I identifies a pendulum andreference numeral 2 a pendulum mounting arrangement which mounts thependulum on the shaft or anchor shah 3. The pendulum shaft 3 alsocarries the so-called anchor 4 and is joumalled in bores of the supportmount 3.

According to a preferred embodiment of the invention that portion of theanchor shah 3 which is remote from the pendulul I is mounted in aspecially constructed journal which is to be described further detailwith reference to FIGS. 3 and 4.

In a device such as is shown in its essential components in FIG. I, itis important that the pendulum in effect is capable of performing freeswinging movements in order to obtain impulses at predetermined timeintervals which should be as much equidistant as possible. Theunavoidable losses due to friction, which serve to dampen the swingingmovement of the pendulum and after a brief period of time would causethe pendulum to stop swinging, are compensated by regular impulses whichare imparted to the anchor 4 by means of the toothed wheel 7 which isdriven by a non illustrated conventional spring drive.

FIGS. Za-Zc illustrate details to show in which manner the driveimpulses are transmitted to the anchor 4 by the toothed wheel 7. Theanchor 4 is fast with the anchor shaft 3 and in FIGS. 20-20 it is shownin various enlarged views. As the Figures show, the anchor 4 comprises afirst or front anchor plate 8 and a second or rear anchor plate 8a whichare connected with one another and with the anchor shaft by connectingportion 9. The toothed wheel 7 is mounted for turning movement in aplane which is normal to the parallel planes of the anchor plates 8 and8a and which also encompasses the center axis of the anchor shaft 3.

For purposes of explanation it will be assumed that one tooth of thewheel 7 has just abutted against the first or front surface of theanchor plate and in so doing has produced an audible impulse or signal.This tooth now slides on the first surface of the anchor plate 8a in onedirection until the pendulum reverses its swinging movement andthereupon the tooth slides on the same surface back in oppositedirection until it comes to the inclined portion of the anchor plate 84.

According to the invention the inclined portion of the anchor plate 8(and also of the anchor plate 8a) is of relatively short but steepconfiguration and constructed as a quaner circle 8d which is followed byan additional quarter circle 8b which leads to the rearwardly directedor second surface of the anchor plate 8. The juncture 8c of quarter 8band 8c is located on a tangent 8e to the plane of the wheel 7. In otherwords, the anchor plate may be considered as being composed of quadraticconfiguration with an axially halved portion of a cylinder secured toits narrow edge. So constructed, and assuming that the anchor plate isproperly adjusted with reference to the wheel 7 on the shaft 3, thepresent invention assures that the anchor 4 receives a drive impulseexactly or almost exactly at the moment in which the pendulum passesthrough its rest or zero position. The drive impulse is brief butforceable and the tooth of the wheel 7 will then slide without beingdamaged or hindered by a sharp front edge of the anchor plate 8- passedthe rear surface of the anchor plate 8 to abut against the front surfaceor first surface of the anchor plate 80 where it produces the nextaudible impulse or signal. This construction of the anchor plates asillustrated and described also assures that if the spring drive or thetoothed wheel 7 should stop, the initially continuing movement of thependulum does not permit the anchor plates to hit the teeth of the wheelbecause these teeth will under all circumstances slide past the curvedor inclined surfaces of the anchor plates.

Having contacted the front surface of the anchor plate 80, the toothdescribed above now slides on this front surface in the manner describedwith respect to the anchor plate 8 until the pendulum reverses itsdirection, at which time the tooth again reverses its direction andexactly or almost exactly at the moment the pendulum passes through itszero position the tooth will slide off the curved edge of the anchorplate 80 beyond the rearward or second surface thereof, at the same timeimparting again to the pendulum a drive impulse while simultaneously thenext tooth of the wheel 7 abuts against the front face of the anchorplate 8 to provide the next audible signal.

In order to assure that the signals and impulses will actually takeplace at precisely spaced intervals, and that further the drive impulseswill always take place precisely or at least substantially precisely atthe moment at which the pendulum passes through its rest position orzero position, and further that the anchor plates will extend in apredetermined manner into the spaces between the teeth of the toothedwheel 7, it is necessary to very precisely adjust the anchor shaft 3.This is accomplished according to the present invention with the aid ofthe arrangements which are discussed hereafter with respect to FIGS. 3and 4.

FIG. 3 shows that the anchor shaft 3 is journalled at its end remotefrom the pendulum I in a bore of a support or carrier 11 which isconnected to a frame 36 by means of two mounting screws 10. Adjacent thebores for the mounting screws the carrier 11 is provided with furtherbores 12 which accommodate eccentric screws 13 which in turn are securedin a manner not separately illustrated to the frame 36. With the aid ofthe eccentric screw I3 it is possible to very precisely adjust theposition of the journal of the carrier 11 with reference to the frame36, and to thereby displace the carrier II with reference to the frame36 laterally as well as upwardly and downwardly. As soon as the properposition for the carrier 11 has been adjusted, the mounting screws 10which pass through bores of the carrier 11, and which bores must ofcourse be greater than the thickness of the shafts of the screws, ortightened in order to fix the selected and adjusted position of thecarrier 11 and therefore of the bore 14 for the anchor shaft 3.

According to FIG. 4 a further end portion of the anchor shaft 3 mountedcarrier 11 is provided 14- with a bushing 15 having an eccentric bore.It is clear that with such a bushing 15 the height of the journallingfor the anchoring shaft 3 cannot be adjusted completely independently ofthe lateral adjustment. However, it has been found that even the use ofsuch a bushing 15 in actual practice has satisfactory results and thatif the bushing is precisely adjusted by means of the adjusting slotillustrating in the drawing, satisfactory results can be obtained,especially if one keeps in mind the great simplicity of adjustment whichis possible with this construction.

The bushing 15 shown in FIG. 4 serves for joumalling the front end ofthe anchoring shaft 3, as shown. However, it is quite clear that it canalso be used for journalling and adjusting the rear end of the anchoringshaft 3 and that for instance the arrangements shown in FIGS. 3 and 4can be combined with one another and that by means of the bushing 15 aprecise adjustment can be carried out after the carrier 11 in such acombined construction has been set by means of the screws 10. If thesetting slot of the bushing 15 need not be accessible from the exterior,then it is advantageous according to the present invention if thehousing wall is provided with a steel plate which may also be madeadjustable by means of a suitable screw arrangementas an abutment forthat portion of the anchoring shaft 3 which passes through the sleeve15, so that by properly constructing the end portion of the anchoringshaft 3 which bears upon the steel plate the friction can be furtherreduced.

It will be appreciated that in order to obtain the benefit of theconstruction according to the present invention, it is necessary thatthe pendulum itself be as long as possible and that its position withreference to the anchor shaft be capable of precise adjustment.Furthermore it is necessary to assure that the center of gravity of thependulum body that is the actual lower weight on the pendulum shaftislocated exactly on the pendulum axis. This is shown by way of example inFIG. 5 where an adjustment arrangement for the pendulum is illustrated.

FIG. 5 shows a device according to the present invention after it ismounted in the housing which has an open side that can be closed bymeans of a plate 33 after the device is mounted in the housing. In theillustrated embodiment that portion of the anchoring shaft 3 whichcarries the pendulum is provided with a pendulum holding arrangement 2which is secured by a counter nut as shown in FIG. I. The pendulum has apendulum shaft 19 which is wider in the region of the pendulum holdingarrangement 2 and which in addition to its bore for the anchor shaft 3is formed with slots 20 located on a circle concentric with this bore.In these slots there extend the shafts of two screws which can bethreaded into the pendulum holding device 2 and which permit positioningof the pendulum shaft in its proper location with reference to thependulum holding device once the proper orientation has been obtained.

possibility for adjusting one is obtained if the stationarily in placeof a simple bore The pendulum shaft 19 carries at its upper region anadjustable pendulum weight 17, and at its lower end portion a lowerpendulum weight or pendulum body 18. The body 18 is mounted on thependulum shaft 19 by means of a connecting element 22 which in theillustrated embodiment is configurated as a screw but which can alsohave the form of a bolt or analogous means. The element 22 can bedisplaced along a transverse slot 23 provided in the body 18 and, inorder for the pendulum shaft 19 to follow the displacements of theelement 22 the interior of the body 18 is provided with a recess 2|which is shown in broken lines in FIG. 5 and whose dimensions are inexcess of those of the lower portion of the pendulum shaft 19 which isto be accommodated in the pendulum body 18. It would of course also bepossible to make the lower end portion of the pendulum shaft 19correspondingly wider and to provide it with a slot corresponding to theslot 23 for making the connecting element displaceable for adjustingpurposes; in this case the connecting element would have to be fast withthe body 18 or, if the body 18 were to be composed of several parts, itwould have to be fast with these parts. If the pendulum shaft isconfigurated as illustrated then it is particularly advantageous toconstruct the pendulum body 18 of one piece and to secure it on thereverse side of the pendulum shaft, that is between the pendulum shaftand the plate 33 of the housing 25, because in this manner the center ofgravity of the device is advantageously displaced closer towards thecenter of the bottom wall of the housing 25 whereby the stability of thedevice is enhanced.

By utilizing the construction shown in FIG. 5 it is possible to adjustthe center of gravity of the pendulum body 18 precisely with referenceto the center axis of the pendulum shaft 19. This, as well as theadjustment of the pendulum rod 19 with reference to the anchor shaft 3is necessary to assure that the periodicity of the pendulum swings ismaintained exactly constant, and also to further assure that aknown-symmetrical arrangement of the pendulum -which would notnecessarily disadvantageously affect the periodicity of the pendulumswinging movementsdoes not disadvantageously affect the regularity ofthe audible signals. The signals are to be entirely regular in theirsuccession, that is the displacement of the pendulum must be assymmetrical with reference to the rest position as possible.

It will be appreciated that adjustments as outlined above are made whenthe device according to the present invention is in a precisely verticalposition. Evidently, therefore, it is desirable that during use thedevice be similarly precisely vertical in order to obtain maximumbenefit from the accuracy of the previous made adjustment. This, ofcourse, requires that the user is able at all times to readily ascertainthat the device is properly vertically oriented, and is able to take thenecessary measures should this not be the case. FIGS. 6 and 7 showembodiments of the invention which make this possible.

In the embodiment of FIG. 6 the upper side of the housing 25 is providedwith a tube-type spirit level 24 which permits a rapid checking whetherat least the side edges of the housing are oriented vertically. This isparticularly important because if the housing is not preciselyvertically oriented, the device will produce audible signalsirregularly. An inclined position will reference to the front and rearedges of the housing as opposed to an inclined position with respect tothe side edges thereofcauses the number of impulses given on the scalenot to be precisely maintained because the inclination of the housing ineffect acts as would a change in the gravity acting on the pendulum.

FIG. 1 shows the bottom of a housing of a device according to thepresent invention, and indicates that the bottom is provided withadjusting screws 26 of which at least one should be providedwhich may ifdesired be provided on the flange projecting beyond the bottom of thehousing. The adjusting screws 26 make it possible to compensate fordisplacements of the housing from the vertical. At the edges oppositethe adjusting screws the housing rests on a projection 35 whichpreferably is connected of one piece with the housing 25 by a molding orpressing operation.

FIG. 8 shows a further arrangement for adjusting the device according tothe present invention. In this embodiment the arrangement for adjustingis effected not as in the FIG. 7, but via a lateral setting screw 32 bymeans of which the entire internal components can be displaced withinthe housing. For this purpose they are mounted turnably on a tiltingaxis 30 by means of two brackets 31, with the tilting axis 30 extendingin the upper part of the housing in parallelism with the anchor shaft 3.The setting screw in the embodiment of FIG. 8 is so constructed that apin which is journalled in the support against turning movement isprovided at its front end with a thread and has a certain amount ofplay, and cooperates with the internal thread provided in a settingscrew 32 which is configurated as a take-along, with the screw 32 alsohaving an external thread which is in mesh with threads provided in thehousing wall.

FIG. 9 shows a complete device according to the present invention inperspective illustration. It will be seen that for such times when thependulum is not in use it can be covered by means of a cap 28. In thisembodiment the tube-type spirit level is replaced with a box level 27 atthe underside of the housing. FIG. 9 also shows that the housing wall isprovided with openings 29 for sound emission which facilitate audibilityof the audible signals and which may be provided at any desired point ofthe housing. In order to provide for a good connection of the cap 28with the remainder of the housing 25, the housing is provided with foldsI6 extending circumferentially, and the cap 28 is similarly providedwith folds l6 interengageable with those of the housing, as shown forinstance in FIG. 5. Snap-action elements may additionally be provided onthe housing and the cap 28 for releasable interengagement.

According to another embodiment of the invention the pendulum shaft 19may be so configurated that its length is greater than the maximumdimension of the housing 25. As shown in FIG. 10 this can beaccomplished in that the pendulum shaft I9 is composed of an upperportion 19a and a lower portion 1% which can be connected by means of aconnecting arrangement 19c which can also be a part of the upper portion190. It is also possible to make the pendulum shaft l9 telescopable inknown manner, or to connect the sections thereof hingedly so that theycan be collapsed when not in use, or to make the pendulum shaft offlexible material so that it can be flexed and accommodated in flexedcondition in the interior of the housing when not in use. Any one ofthese possibilities assures that the housing which in any case will havea height of less than 150 mm can be made still smaller, or that theeffective length of the pendulum during the operation of the device canbe increased, without having to increase the dimensions of the housing.The construction of the pendulum or the pendulum shaft according to thepresent invention thus can be made use of not only with devices whichutilize the particularly configurated anchoring plates according to thepresent invention, but any devices of the type under discussion.However, the inventive construction of the pendulum shaft isparticularly advantageous in conjunction with the other features of theinvention.

FIG. I also shows a particularly advantageous construction for the upperadjustable pendulum weight 17. It is already known that these weightsconventionally use a spring which on the one hand serves to maintain thependulum weight 17 at a preselected position longitudinally of thependulum rod 19, and which on the other hand snaps into transversegrooves provided in the pendulum shaft I9, with the grooves beinglocated in accordance with the selected number of swing intervals.Heretofore it was customary to construct this spring as a separatecomponent which was connected with the pendulum weight 17 itself, withthe latter preferably consisting of lead or the like and being composedof a front plate, the actual weight secured to the front plate, and thespring. The front plate essentially had no other purpose than to improvethe aesthetic appearance because they almost exclusively used leadweights and tend to appear rather unattractive due to oxidation over aperiod of time. The present invention in the embodiment illustrated inFIG. 10 proposes to simplify the construction of the adjustable weight17 by constituting the spring as a portion of the front plate itself.Thus, the front plate is constructed of a springy material, for instancespring steel, and in the region of the pendulum shaft 19 it is providedwith two slots which extend essentially in parallelism with thelongitudinal axis of the pendulum shaft 19 so that a springy tongueexists which is connected at its opposite ends with the remainder of thefront plate. By lightly displacing this tongue inwardly there is thenobtained the spring 39 which engages the pendulum shaft 19. Such aconstruction makes the production of the upper adjustable pendulumweight I7 less expensive than heretofore, a consideration which isparticularly advantageous and important in a small-dimensioned metronomeaccording to the present invention because the price in such smalldevices is of course of particular importance. Of course, it will beappreciated that this aspect of the invention can also be used toadvantage with conventional larger metronomes.

Finally, FIGS. I 1-14 illustrate still a further embodiment of theinvention in which means are provided for increasing the audibility ofthe signals produced by the device. For this purpose the housing 25 isprovided in one of its walls with a vibratory membrane 27 which isadvantageously but not excusivelyof heat steel. The rear end portion ofthe anchor shaft 3 abuts against this membrane or diagraphram 37 wherebythe individual audible signals are reliably and advantageouslytransmitted to the diaphragm with the accoustical signal being emittedthrough an opening 38 which is located behind or exteriorly of thediaphragm 37 and which preferably conically diverges in outwarddirection. In this construction the diaphragm 37 can of course alsoserve as an abutment for the anchor shaft 3.

Again it will be appreciated that the embodiment in FIGS. 11-14 can beused not only in conjunction with the other features according to thepresent invention, but can also be used in conventional metronomes ofall types. However, it is especially advantageous in conjunction withthe device according to the present invention because it assures properaudibility of the signals even if the force with which the teeth of thewheel 7 abut against the plates 8 and 8a is reduced, which in turn makesit possible to use a spring drive of less power and therefore a springdrive which is less expensive.

In all embodiments of the invention it is advantageous, particularlybecause the device is to be readily transportable, to provide the frontside of the housing or the front plate thereof with an arresting meansfor preventing the pendulum from swinging when this is not desired. AsFIG. 6 shows such an arresting device can be configurated as anarresting bracket 34. However, as shown in FIGS. 12-14 a preferredembodiment of such a device is in form of a projection 40 provided atthe center of the front edge at the upper side of the housing 25, whichin turn is provided with a recess the width of which is approximately asgreat as the width of the pendulum shaft 19. The depth of the recessalso corresponds approximately to the depth of the shaft 19. To assure aproper arresting of the tip of the shaft I9 in the recess the open frontside of the recess at the right and the left may be provided with asmall bead or the like so that the free opening is somewhat smaller thanthe width of the shaft 19 which is then pressed with light pressure intothe recess until it slides past the beads and abuts against the rearwall of the recess.

The upper side of the projection preferably is not flush with the upperside of the housing, but slightly downwardly displaced with referencethereto. This makes it possible to pro vide the cap 28 with acorresponding recess 41 which then overlies the projection so that thelatter is no longer visible when the housing is closed by the cap 28.

This latter possibility is partially shown in FIGS. "PM, so that aportion of the upper side of the projection is visible when the housingis closed whereas another portion is covered by the cap 28. Thisembodiment has the advantage that the strength of the arresting element,which is generally limited by the wall thickness of the housing 25, isincreased which is evidently desirable.

It will be understood that each of the elements described above, or twoor more together, may also find a useful application in other types ofconstructions differing from the types described above.

While the invention has been illustrated and described as embodied in adevice for measuring repetitive identical time intervals, it is notintended to be limited to the details shown, since various modificationsand structural changes may be made without departing in any way from thespirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for various applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning and range of equivalence of thefollowing claims.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended l. A device for measuring repetitive identicaltime intervals, particularly for musical and medical use, comprising ahousing; a shaft journalled in said housing for turning movement aboutan axis and having a first portion and a second portion; a pendulum fastwith said first portion and elongated radially of said axis for swingingmovement about the same; a pair of anchor plates mounted on said secondportion in axially spaced parallel planes for movement therewith, saidplates each having a first surface both facing in one axial directionand a second surface both facing in the opposite axial direction, andeach of said first surfaces being inclined to an edge portion extendingat least substantially radially of said axis and convexly curved on asmall radius in direction axially of said shaft towards the respectivelyassociated second surface; and a circumferentially toothed wheel mountedand biased for rotation in a plane at least substantially normal to saidparallel planes and paralleling said axis, consecutive teeth of saidwheel engaging first one of said first surfaces so as to slide along thesame to said edge portion and to slide on said edge portions past theassociated second surface while concomitantly imparting to said platesand thereby said pendulum a turning impulse with successive audibleabutment on the other of said first surfaces, and for sliding along theother of said first surfaces and associated edge portions beyond theassociated second surface while simultaneously a consecutive tooth abutsthe first one of said surfaces.

2. A device as defined in claim 1', and further comprising weight meansmounted on said pendulum displaceable longitudinally of the same towardsand away from said axis for concomitantly varying the period of swing ofsaid pendulum.

3. A device as defined in claim 1, wherein the convex curva ture of therespective edge portions resembles the outline of an axially bisectedcircular cylinder whose diameter corresponds to the distance between thefirst and second surface of the respective anchor plate.

4. A device as defined in claim 1, said anchor plates and toothed wheelbeing composed of material so selected as to have minimum frictionduring relative contact between said toothed wheel and the respectiveanchor plates.

5. A device as defined in claim 4, wherein said toothed wheel is madefrom acetal resin and said anchor plates from steel.

6. A device as defined in claim 1, said shaft having opposite endportions; and further comprising journal means journalling said oppositeend portions and wherein at least one of said journal means journals theassociated end portion adjustably.

7. A device as defined in claim 6, said one journal means comprising ajournal support and a bushing turnably mounted in said journal supportand having an axially extending eccentric journal bore in which saidassociated end portion is accommodated.

8. A device as defined in claim 6, said one journal means comprising asupport, a journal for said associated end portion, and a pair ofexcenter screws on opposite sides of said journal and acting upon saidsupport in a sense displacing the same with reference to the otherjournal means.

9. A device as defined in claim 1; and mounting means mounting saidpendulum on said shaft adjustably displaceable with reference to thesame.

10. A device as defined in claim 9, said mounting means comprising apendulum-holding element secured to said shaft and having a passage forreceiving a portion of the pendulum shaft, and at least one set screwthreaded into said element so as to project into said passage and havinga screw portion extending into a slot provided in said pendulum shaft.

11. A device as defined in claim 1, said pendulum having a pendulum shahand a pendulum body; and wherein said pendulum body is so configuratedas to afford a lowest possible center of gravity for said pendulumconsonant with a maximum permissible length of said pendulum indirection normal to said shaft.

12. A device as defined in claim 11, said pendulum body having the shapeof a sector of a circular disk having a blunt tip provided with an edgeface which extends normal to a radial center line of said sector.

13. A device as defined in claim 1, said pendulum having a pendulumshaft and a pendulum body mounted on said pendulum shaft displaceablelongitudinally of the same.

14. A device as defined in claim 13, said pendulum body having a recessand a transverse slot, said recess being larger than the outline of thatportion of said pendulum shaft which is received therein; and furthercomprising a connecting element connecting said pendulum body with saidpendulum shaft and being slidable in said transverse slot.

15. A device as defined in claim 14, said transverse slot having theshape ofa portion of are centered on the center axis of said pendulumbody.

16. A device as defined in claim 1, said housing having a bottom wall;and further comprising at least one adjusting screw on said bottom wallexteriorly of said housing for enabling adjusting of the orientation ofthe latter with reference to a surface on which said bottom wall issupported.

17. A device as defined in claim 1, said housing having an upper portionand a lower portion; and further comprising a pair of mounting membersmounting said pendulum, anchor plates and wheel turnable about a turningaxis in said upper portions and paralleling said shaft.

18. A device as defined in claim 17, said wheel comprising a springdrive; and further comprising a set screw for arresting said springdrive in a desired angular position upon turning about said turningaxis.

19. A device as defined in claim 1; and further comprising soundapertures in said housing for facilitating emission of sound therefrom.

20. A device as defined in claim 1, wherein said housing issubstantially cubical and has an open side for insertion and removal ofthe components accommodated in said housing.

21. A device as defined in claim 20, said housing having a plurality ofperipheral walls bounding said open side and provided with a fold; andfurther comprising a correspondingly folded cap member engageable withsaid folds of said peripheral walls for removably covering said openside.

22. A device as defined in claim 1, said housing having a front wallprovided with a projection having a recess; and wherein said pendulum islocated outwardly adjacent said front wall and comprises a pendulumshaft partially receivable in said recess for arresting said pendulumagainst undesired swinging motion.

23. A device as defined in claim 1, said housing having a minimumdimension and a maximum dimension; and wherein said pendulum comprises apendulum body and a pendulum shaft which connects said pendulum bodywith said shaft, said pendulum shaft having a longitudinal dimensiongreater than said maximum dimensions of said housing.

24. A device as defined in claim 23, wherein said pendulum shaft iscomposed of a plurality of telescopable sections.

25. A device as defined in claim 23, wherein said pendulum shaft iscomposed of a plurality of hinged collapsible sections.

26. A device as defined in claim 23, wherein said pendulum shaft iscomposed of a plurality of connectable sections.

27. A device as defined in claim 23, wherein said pendulum shaft iscomposed of flexible material and is accommodatable in flexed conditionin the interior of said housing.

28. A device as defined in claim 1, said housing having a peripheralwall provided with an oscillatable diaphragm.

29. A device as defined in claim 28, wherein said diaphragm is a steeldisk and constructed as an abutment for an end portion of said shaftwhich is remote from said pendulum.

30. A device as defined in claim 29, said diaphragm being located on aninwardly facing side of said wall; and wherein said wall is provided atthe outwardly facing side thereof with an opening which registers withsaid diaphragm and diverges inwardly in direction towards the same.

31. A device as defined in claim 30, wherein said opening divergesconically.

32. A device as defined in claim I, said pendulum comprising a pendulumshaft carried by said shaft, a pendulum body on said pendulum shaft, anda pendulum weight also on said pendulum shaft and wherein said weight isprovided with a passage through which said pendulum shaft extends and aspringy portion of said weight is deflected into said passage and intofrictional engagement with said pendulum shaft.

33. A device as defined in claim I, said housing having an upper wallprovided with a box level.

34. A device as defined in claim 1, said housing having an upper wallprovided with a tubular level.

35. A device as defined in claim 34, said tubular level com prising aliquid-containing tube having a longitudinal axis which extends inparallelism with the plane of swinging movement of said pendulum.

I B t i i

1. A device for measuring repetitive identical time intervals,particularly for musical and medical use, comprising a housing; a shaftjournalled in said housing for turning movement about an axis and havinga first portion and a second portion; a pendulum fast with said firstportion and elongated radially of said axis for swinging movement aboutthe same; a pair of anchor plates mounted on said second portion inaxially spaced parallel planes for movement therewith, said plates eachhaving a first surface both facing in one axial direction and a secondsurface both facing in the opposite axial direction, and each of saidfirst surfaces being inclined to an edge portion extending at leastsubstantially radially of said axis and convexly curved on a smallradius in direction axially of said shaft towards the respectivelyassociated second surface; and a circumferentially toothed wheel mountedand biased for rotation in a plane at least substantially normal to saidparallel planes and paralleling said axis, consecutive teeth of saidwheel engaging first one of said first surfaces so as to slide along thesame to said edge portion and to slide on said edge portions past theassociated second surface while concomitantly imparting to said platesand thereby said pendulum a turning impulse with successive audibleabutment on the other of said first surfaces, and for sliding along theother of said first surfaces and associated edge portions beyond theassociated second surface while simultaneously a consecutive tooth abutsthe first one of said surfaces.
 2. A device as defined in claim 1; andfurther comprising weight means mounted on said pendulum displaceablelongitudinally of the same towards and away from said axis forconcomitantly varying the period of swing of said pendulum.
 3. A deviceas defined in claim 1, wherein the convex curvature of the respectiveedge portions resembles the outline of an axially bisected circularcylinder whose diameter corresponds to the distance between the firstand second surface of the respective anchor plate.
 4. A device asdefined in claim 1, said anchor plates and toothed wheel being composedof material so selected as to have minimum friction during relativecontact between said toothed wheel and the respective anchor plates. 5.A device as defined in claim 4, wherein said toothed wheel is made fromacetal resin and said anchor plates from steel.
 6. A device as definedin claim 1, said shaft having opposite end portions; and furthercomprising journal means journalling said opposite end portions andwherein at least one of said journal means journals the associated endportion adjustably.
 7. A device as defined in claim 6, said one journalmeans comprising a journal support and a bushing turnably mounted insaid journal support and having an axially extending eccentric journalbore in whiCh said associated end portion is accommodated.
 8. A deviceas defined in claim 6, said one journal means comprising a support, ajournal for said associated end portion, and a pair of excenter screwson opposite sides of said journal and acting upon said support in asense displacing the same with reference to the other journal means. 9.A device as defined in claim 1; and mounting means mounting saidpendulum on said shaft adjustably displaceable with reference to thesame.
 10. A device as defined in claim 9, said mounting means comprisinga pendulum-holding element secured to said shaft and having a passagefor receiving a portion of the pendulum shaft, and at least one setscrew threaded into said element so as to project into said passage andhaving a screw portion extending into a slot provided in said pendulumshaft.
 11. A device as defined in claim 1, said pendulum having apendulum shaft and a pendulum body; and wherein said pendulum body is soconfigurated as to afford a lowest possible center of gravity for saidpendulum consonant with a maximum permissible length of said pendulum indirection normal to said shaft.
 12. A device as defined in claim 11,said pendulum body having the shape of a sector of a circular diskhaving a blunt tip provided with an edge face which extends normal to aradial center line of said sector.
 13. A device as defined in claim 1,said pendulum having a pendulum shaft and a pendulum body mounted onsaid pendulum shaft displaceable longitudinally of the same.
 14. Adevice as defined in claim 13, said pendulum body having a recess and atransverse slot, said recess being larger than the outline of thatportion of said pendulum shaft which is received therein; and furthercomprising a connecting element connecting said pendulum body with saidpendulum shaft and being slidable in said transverse slot.
 15. A deviceas defined in claim 14, said transverse slot having the shape of aportion of arc centered on the center axis of said pendulum body.
 16. Adevice as defined in claim 1, said housing having a bottom wall; andfurther comprising at least one adjusting screw on said bottom wallexteriorly of said housing for enabling adjusting of the orientation ofthe latter with reference to a surface on which said bottom wall issupported.
 17. A device as defined in claim 1, said housing having anupper portion and a lower portion; and further comprising a pair ofmounting members mounting said pendulum, anchor plates and wheelturnable about a turning axis in said upper portions and parallelingsaid shaft.
 18. A device as defined in claim 17, said wheel comprising aspring drive; and further comprising a set screw for arresting saidspring drive in a desired angular position upon turning about saidturning axis.
 19. A device as defined in claim 1; and further comprisingsound apertures in said housing for facilitating emission of soundtherefrom.
 20. A device as defined in claim 1, wherein said housing issubstantially cubical and has an open side for insertion and removal ofthe components accommodated in said housing.
 21. A device as defined inclaim 20, said housing having a plurality of peripheral walls boundingsaid open side and provided with a fold; and further comprising acorrespondingly folded cap member engageable with said folds of saidperipheral walls for removably covering said open side.
 22. A device asdefined in claim 1, said housing having a front wall provided with aprojection having a recess; and wherein said pendulum is locatedoutwardly adjacent said front wall and comprises a pendulum shaftpartially receivable in said recess for arresting said pendulum againstundesired swinging motion.
 23. A device as defined in claim 1, saidhousing having a minimum dimension and a maximum dimension; and whereinsaid pendulum comprises a pendulum body and a pendulum shaft whichconnects said pendulum body with said shaft, said pendulum shaft havinga longItudinal dimension greater than said maximum dimensions of saidhousing.
 24. A device as defined in claim 23, wherein said pendulumshaft is composed of a plurality of telescopable sections.
 25. A deviceas defined in claim 23, wherein said pendulum shaft is composed of aplurality of hinged collapsible sections.
 26. A device as defined inclaim 23, wherein said pendulum shaft is composed of a plurality ofconnectable sections.
 27. A device as defined in claim 23, wherein saidpendulum shaft is composed of flexible material and is accommodatable inflexed condition in the interior of said housing.
 28. A device asdefined in claim 1, said housing having a peripheral wall provided withan oscillatable diaphragm.
 29. A device as defined in claim 28, whereinsaid diaphragm is a steel disk and constructed as an abutment for an endportion of said shaft which is remote from said pendulum.
 30. A deviceas defined in claim 29, said diaphragm being located on an inwardlyfacing side of said wall; and wherein said wall is provided at theoutwardly facing side thereof with an opening which registers with saiddiaphragm and diverges inwardly in direction towards the same.
 31. Adevice as defined in claim 30, wherein said opening diverges conically.32. A device as defined in claim 1, said pendulum comprising a pendulumshaft carried by said shaft, a pendulum body on said pendulum shaft, anda pendulum weight also on said pendulum shaft and wherein said weight isprovided with a passage through which said pendulum shaft extends and aspringy portion of said weight is deflected into said passage and intofrictional engagement with said pendulum shaft.
 33. A device as definedin claim 1, said housing having an upper wall provided with a box level.34. A device as defined in claim 1, said housing having an upper wallprovided with a tubular level.
 35. A device as defined in claim 34, saidtubular level comprising a liquid-containing tube having a longitudinalaxis which extends in parallelism with the plane of swinging movement ofsaid pendulum.